Apparatus for making uniform mats of inorganic fibers



Dec. 29, 1970 J. PAOLEYTTI 3,551,250

APPARATUS FOR MAKING UNIFORM MATS OF INORGANIC FIBERS Filed D80. 29,1967 2 Sheets-Sheet l SUCTION BOX 0: 5 g g. E a; f

I N VENTOR.

ATTORNEYS FOEE/PT J. P404 77/ D 9. 1970 R. J. PAQLETTI APPARATUS FORMAKING UNIFORM MATS OF INORGANIC FIBERS 2 Sheets-Sheet 2 Filed Dec. 29,1967 lll INVHNTOR F05 (Z P404 [77/ QUMMM RNEYS United States Patent OAPPARATUS FOR MAKING UNIFORM MATS F INORGANIC FIBERS Robert J. Paoletti,Toledo, Ohio, assignor to Owens- Corning Fiberglas Corporation, acorporation of Delaware Filed Dec. 29, 1967, Ser. No. 694,582 Int. Cl.B29j 5/00; B32b 5/16; DZlb 1/04 US. Cl. 15637 0 7 Claims ABSTRACT OF THEDISCLOSURE A mat of inorganic fibers is made by sucking an air streamcarrying glass fibers and a spray of organic binder down upon the topsurface of a foraminous conveyer. A suction box is positioned below theconveyer to draw the material onto the top of the conveyer and thefibers and spray are confined to the top surface of the conveyer by aforming hood. The side walls of the forming hood comprise a pair ofparallel endless conveyers having adjacent flights which form oppositevertical side walls of the hood. The adjacent conveyers have verticalhead pulleys positioned adjacent the tail pulley of the horizontalconveyer and have tail pulleys spaced in the direction of the movementof the horizontal conveyer from its tail pulley. The conveyer elementsof the adjacent flights extend generally vertically and travel in theopposite direction to the horizontal conveyer. The elements of theparallel conveyers have smooth surfaces and are hinged together belowthese smooth surfaces so that the elements separate as they move aroundthe head pulleys. A flow of wash water flows over and between theelements as they round the head pulley, and an end wall extends betweenthe adjacent flights in the direction of the horizontal conveyermovement from these parallel head pulleys. After the parallel conveyerelements round their head pulleys they are squeegeed to remove the wateras they travel to their tail pulleys, following which they again moveinto position to form hood walls which direct the fiber and binder downupon the horizontal conveyer. The vertical conveyer elements are spaceda slight distance from the top surface of the horizontal conveyer, andthe lower back sides of these conveyer elements ride along a side of alongitudinally extending board positioned just above the top surface ofthe horizontal conveyer outside of the forming area. The wash water isrecirculated a number of times, and a side stream enriched with thebinder removed from the parallel conveyers is fed to the binder mixtanks and used to form part of the binder solution.

BACKGROUND OF THE INVENTION Prior to the invention, mats of mineralfibers that are bonded together by an organic binder have been made bypulling the minarl fibers into a forming hood that is positioned over ahorizontal conveyer. The fibers are carried along in a large volume ofgases into which a binder is sprayed, and the fibers and spray which arefed to the forming hood are sucked down upon the conveyer by a suctionbox positioned beneath the top surface of the horizontal conveyer. Thefibers are attenuated and carried along by a large volume of theseturbulent gases, so that the fibers and the spray impinge upon the wallswhich form the forming hood. The walls forming the forming hood have forthe most part been stationary, and some of the wetted fibers collect onthe walls of the forming hood where they stick for a period of time.Some of these fibers fall down onto the surface of the mats being formedas wads of fibers, and others remain on the side walls of the forminghood until the equipment is shut down and cleaned. The wads of glassfibers which fall off of the 3,551,250 Patented Dec. 29, 1970 walls ofthe forming hood are often wetter than the fibers on the surface of theconveyer, and these wads leave imperfections in the mat being formed.Not only are these wads not integrated well with the rest of the fibersof the mat, but their binder composition is different from that of themat, so that when the mat containing the wads is cured in an oven, theyvisually stand out as an imperfection.

In one instance with which applicants are aware, the side walls of thehood move in the same direction and speed as the horizontal conveyer tocreate a minimum of disturbance of the side edges of the mat. Long flatmetal plates have been laid upon the top surface of the horizontalconveyer to act as a seal, and the bottom of the vertical side wallshave slid along on top of the steel strips. The movable side walls havebeen moved forwardly around head pulleys, washed with water, and thenmoved back to the beginning of the horizontal conveyer. Mats formed bysuch apparatus have not achieved uniformity, and it has not been knownwhat has caused the imperfections.

An object of the present invention is the provision of a new andimproved apparatus for making bonded mats of inorganic fibers which isdevoid of wads and blemishes that are discernible to the naked eye.

SUMMARY I It has been discovered that a more uniform mat of randomlyoriented inorganic fibers bonded together at points of contact by abinder can be made in apparatus wherein the fibers are collected on ahorizontal conveyer between side walls which move in the oppositedirection from that of the horizontal conveyer. The mat has less binderspots and Bakelite spots, and the cure of the binder throughout the matis more uniform. In the preferred embodiment, a transverse vertical wallis positioned between the movable vertical side walls adjacent thebeginning of the top flight of the horizontal conveyer, and thetransverse wall is preferably slightly out of contact with the movableside Walls. Any material adhering to the movable side Walls usuallypasses the transverse wall and moves around a head pulley of theconveying mechanism forming the vertical side walls where a flow ofwater downwardly over the movable walls washes debris therefrom,following which the vertical walls are dried. It appears that thisprocedure generally eliminates the binder spots and Bakelite spotsadjacent the edges of the mat which is formed by the apparatus; and italso appears that the binder cure across the width of the mat is moreuniform. The movable vertical side walls preferably also have an airspace or clearance between their bottom edges and the top surface of thehorizontal conveyer to allow a slight controlled air flow therebetweenwhich has a beneficial effect upon the uniformity of the edges of themat which is produced. The apparatus appears to remove a largeproportion of the wads of fiber and binder which normally form binderspots and Bakelite spots from the forming area. The wads are washed offof the walls and the binder is leached out of the wads. This wash wateris recirculated a number of times and a side stream is used to makefresh binder solution. The binder in the side stream has no appreciableadvance in the cure of the resin, so that the binder which previouslyformed Bakelite spots is now uniformally distributed throughout the mat.The mat which is produced has more uniform moisture content and moreuniform cure throughout than do mats made by prior art apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view ofapparatus embodying principles of the present invention; and

FIG. 2 is a fragmentary plan view of the structure which forms theimmediate mat forming area of the apparatus shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus shown in thedrawings for producing mat generally comprises a glass furnace having aforehearth 12 proceeding therefrom to deliver the molten glass to aplurality of forming stations 14, one of which is shown in solid linesand others of which are shown by dotted lines. The bottom of theforehearth at each forming station is provided with a metal plate 16having a hole therein for delivering a stream of molten glass 18 intothe hollow shaft 20 of a motor driven centrifuge 22. A motor 24surrounds the top end of the shaft 20 and a centrifuge basket 26 havinga plurality of openings in its other periphery is fixed to the bottomend of the hollow shaft 20. A plurality of molten streams of glass arethrown from the openings in the basket 26, and a downwardly flow ofgases over the edge of the basket 26, produced by means not shown,causes the molten streams of glass to be attenuated into small filamentsthat are dispersed in the stream of gases in what are known as a veil28. The apparatus of the present invention will include a multiplicityof veil producing mechanisms 14 and four are shown in FIG. 1.

The glass fibers from the various veils 28 are collected on the topforaminous flight 30 of a horizontal conveyor 32 having a head pulley 34and tail pulley 36. A suction box 38 is positioned beneath the topflight 32 to draw the large volume of gases downwardly through the topflight 30 and cause the fibers in veils to be deposited on the topsurface of the conveyor 30 in the form of a mat 40. The swirling volumeof gases and fibers which constitute the veils do not assume thecylindrical shape shown in the drawings, but spread out violently in alldirections and must be confined to the top surface of the conveyor 30.In the embodiment shown, the fibers and gases are confined to the topsurface 30 by a pair of parallel side walls 42, a stationary rear endwall 44, a front end wall 46, and roll gate 48.

The mat of loose fibers that is formed within the confines of the wallsabove described (hereafter called forming hood), is bonded together by abinder that is sprayed into the confines of the forming hood through aplurality of nozzles 50. The binder that is used is an aqueous solutionwhich permeates the mat. Droplets of the binder solution are held atcrossover points of the fibers forming the mat, and the binderimpregnated mat 40 is delivered to a cure oven 52 where the water isremoved and the binder cured to a thermostat condition. In the presentinstance, the binder which is used is a phenol formaldehyde resite. Thebottom edge of the front end wall 46 is positioned well above the heightof the fibers collected in the forming hood, and the rear edge of theroll gate 48 is generally tangent to the bottom edge of the front endwall 46 to generally seal off the forming hood and smoothen out thefibers issuing from the forming hood.

The veil that is formed by the apparatus 14 does not have a uniformdistribution of the glass fibers and includes wads of these fibers whichbecame saturated with binder and were thrown against the side walls ofthe forming hood. Prior to the present invention, stationary side wallshave been used, and it has been necessary to shut down the mat makingapparatus above described periodically, to clean off an accumulation ofthe wads of fibers and binder that adhere hereto. Prior to the presentinvention, this has been accepted as a necessary part of the operationof forming mat. The prior art was also aware of the fact that the matproduced by the apparatus was nonuniform and contained what is calledbinder spots and Bakelite spots. Binder spots are areas which areincompletely cured, and Bakelite spots are areas which have more than anaverage amount of binder and which is fully cured, Because the areawithin the forming hood is extremely turbulent, however, the prior artdid not know how the prevent the formation of binder spots and Bakelitespots, since their formation could not be visually observed. Theapparatus of the present invention produces mat which is considerablymore uniform than has been produced by the prior art, and by observingits operation the reasons for binder spots and Bakelite spots in theprior art are now apparent. In the prior art, the binder spots andBakelite spots were most numerous adjacent the side edges of the mat andit is postulated that these imperfections were formed by wads of binderimpregnated fibers which had previously adhered to the side walls of theforming hood and which were loosened by the turbulent gases to cause thewads to fall down onto the mat adjacent the side edges of the mat. I11one instance, the side walls of the forming hood were made to move alongwith the top flight 30 of the horizontal conveyor, and in this instancethe binder spots and Bakelite spots still existed. I

In the present instance, the parallel side walls 42 are formed as partof endless conveyors 54, the adjacent parallel flights 42 of which movein the direction opposite from that of the top flight 30 of thehorizontal conveyor 32. As such, the movable side walls 42 rub againstthe side edges of the mat being produced, but it has been found not totear or unduly damage the side edges of the mat.

Each of the endless side wall conveyers 54 are formed from a pluralityof vertical elements which are fastened to and are carried by top andbotom roller chains which move about sprockets forming head pulleys 56and tail pulleys 58. The sprockets forming each tail pulley 58 areconnected together by a shaft 60, and each shaft 60 is in turn driven bymotor and gear reducer 62, only one of which is shown. The endless sidewall conveyers 54 are constructed in such a way that the space betweenthe verticle conveyer elements open up, or become enlarged as they roundthe head pulley 56 to loosen 'and expose any debris accumulated therein.The debris between the vertical conveyer elements is washed from theside wall conveyers by wash nozzles 64 which project a stream of wateragainst the top edge of the respective side wall conveyer outwardly ofthe end wall 44 as the vertical elementsround the head pulley 56. Theflow of wash water issuing from the nozzle 64 washes wads and otherdebris downwardly into a recovery pan 66 from which the wash water flowsto a separator 68 which removes the glass fibers. The wash water isrecirculated by a wash water pump 70 to the nozzles 64. The binder thatis removed from the wads and from the side walls becomes dissolved inthe wash water and a side stream of the Wash water is pumped by pump 72to a binder preparation tank 74 where it is used to formulate theaqueous binder solution. The aqueous binder solution is in turn pumpedby pump 76 to the binder nozzles 50 previously described. After thevertical conveyer elements are washed by the flow of water from thenozzle 64, the vertical elements move forwardly to a squeegee 78positioned at an angle to force the water downwardly into the recoverypan 66. The squeegee 78 is located adjacent the head pulley 56 and anywater that remains after the squeegee operation, has an appreciable timeto evaporate before the elements round the tail pulley to move intoposition in the forming hood.

The apparatus above described has advantages which at first may not beapparent. In comparing the mat which it produces from that of the priorart, it is noted that the mat has less binder spots and Bakelite spots.It is believed that binder spots and Bakelite spots were caused by wadsof fiber and binder falling from the side walls onto the side edges ofthe mat. In the apparatus of the present invention, it will be seen thatthose wads which stick onto the wall are not removed by a wiping actionof the rear end wall 44, but that clearance is provided to allow thewads to move out of the forming area Where they are washed free of thevertical conveyer elements. The wads are washed into the recovery panwhere the binder is leached therefrom, and this occurs so quickly thatthe binder does not have a chance to advance in cure from its A stage.The binder, therefore, can be recirculated and used over again withoutharmful effects. In some instances, there will be a rush of air into theforming hood through the clearance between the rear end wall 44 and themovable side walls 58 which will cause some of the wads to fall downupon the conveyer mat. With the apparatus of the present invention,these wads will be one of the first materials that are collected on thehorizontal conveyer 30 and can have excess binder removed therefrom dueto the increased length of travel over the suction box. In addition, thebulk of the glass fibers forming the mat, fall on top of the wads sothat the wads become more thoroughly integrated and can not be seen fromthe top surface of the mat which is formed. It will also be seen thatthe front wall 46 in the present instance does not wipe wads from themovable side walls as might occur if the side walls moved in the samedirection as the horizontal conveyer 30. It will further be seen thatoptimum conditions are provided by the washing of the movable side wallsadjacent the head pulleys 56 rather than at the tail pulleys 58, sincethe wash water has no chance of falling on the side edges of the mat aswould occur if washed at the tail pulleys 58. Wash water on the matwould, of course, leach binder from the mat and give areas which weredepleted of the binder.

It will now be apparent that the objects heretofore enumerated as wellas others have been achieved, and that there has been provided a new andimproved apparatus which produces more uniform mat for reasons which arenow apparent by observation of the highly turbulent gases and fiber fedinto the forming area.

While the invention has been described in considerable details, we donot wish to be limited to the particular embodiments shown anddescribed, and it is our intention to cover hereby all noveladaptations, modifications, and arrangements thereof which come withinthe practice of those skilled in the art to which the invention relates.

I claim:

1. Apparatus for producing a mat of mineral fibers Wetted by a binderwith the width of the mat being many times greater than the thickness ofthe mat, said apparatus comprising: a pair of generally vertical endlesswall mechanisms having adjacent generally parallel runs positioned apartby a distance corresponding generally to the width of the mat, agenerally horizontal movable fiber collection surface extendingtransversely to said runs to define one major surface of the mat, saidfiber collection surface moving in one endwise direction of said runs,means discharging mineral fibers and a liquid binder forming materialbetween said runs and onto said fiber collection surface to continuouslyadd increments of fibers to build up the thickness of the mat normal toits major surface, and means moving said runs in the opposite endwisedirec- 6 tion from the direction of movement of said fiber collectionsurface.

2. The apparatus of claim 1 wherein said runs move to a turn aroundregion located at the upstream end of said fiber collection surface.

3. The apparatus of claim 2 including Washing means for said verticalendless wall mechanisms located at the upstream end of said mechanism.

4. The apparatus of claim 3 including binder distribution means fordistributing a binder in a water vehicle to said fibers, collectionmeans for water vehicle delivered to said washing means after it hasWashed the vertical endless wall mechanism, means for preparing binderdistributed throughout the water and delivering it to said binderdistribution means, and means delivering the water and binder from saidcollection means to said binder preparation means.

5. Apparatus for producing a mat of glass fibers wetted by a binder withthe Width of the mat being many times greater than the thickness of themat, said apparatus comprising: a pair of generally vertical wallmechanisms with one mechanism having a run positioned adjacent to andfacing a corresponding run of the other mechanism and with at least aportion of said facing runs being parallel, said generally parallel runsbeing positioned apart by a distance corresponding generally to thewidth of the mat, a movable fiber collection surface extendingtransversely to said parallel portions of said runs to define one majorsurface of the mat, said fiber collection surface moving in one endwisedirection of said runs, means discharging said fibers and an aqueoussolution of a binder between said runs and onto said fiber collectionsurface to continuously add increments of fibers to build up thethickness of the mat said runs in the opposite end wise direction fromthe direction of movement of said fiber collection surface to a turnaround region, and washing means for said vertical endless wallmechanisms.

6. The apparatus of claim 5 wherein said endless wall mechanisms includevertical wall flights arranged to move apart as they round said turnaround regions.

7. The apparatus of claim 6 wherein said'washing means applies washwater to said vertical wall flights when moved apart, said apparatusfurther including: means for collecting the wash Water from the verticalwall flights, and means recirculating the wash Water from saidcollection means to said binder spraying means.

References Cited UNITED STATES PATENTS 9/1943 Drill et a1. l56-372X6/1950 Joa l9l56X U.S. Cl. X.R. 156-372; 264-l1 5

